mfc@houxj.UUCP (M.CAGGIANO) (05/08/85)
In response to a recent article about tweeter placement I have done some research with respect to phase distortion and human perception. The position of the tweeter with respect to the other drivers and position of the audience does effect the relative phases of components within a complex. However, "because such changes in phase occur frequently in nature our hearing is relatively indifferent to them---a sawtooth sounds much like a glottal wave regardless of phase difference" These quotes are taken from Perception and the Senses by Brown et al. These are experimental psychologists who do thousands of experiments and make up a big graph (I prefer to do one experiment and make thousands of graphs). Basically the human brain cannot perceive phase distortion within a sound complex emanating from the same source. This is why you can move the tweeter around a few inches or even reverse its polarity and not notice a difference in quality of sound. A good demonstration of this would be insert a dpdt switch in line with a tweeter of a 2 or 3 way system and have a friend toggle the switch while listening. This is not the same phenomenon as locating the source of a sound through phase differential between your two ears (this is why a dog will tilt its head several times at different angles when trying to locate a strange sound). Michael Caggiano